In general, a rotary device such as a motor having a rotary shaft employs a bearing for supporting the rotary shaft. Such a bearing includes a ball bearing, an air bearing, a fluid bearing, a magnetic bearing, and the like.
A magnetic bearing supports rotation of a rotary shaft by using a magnetic force. Thus, the magnetic bearing includes an electromagnet for generating a magnetic force, and a sensor for detecting a position of the rotary shaft floated by the magnetic force generated in the electromagnet.
Further, a potting compound is filled in a space between a bearing housing and the electromagnet to reinforce a mechanical strength of the electromagnet. When contaminations of the electromagnet and the sensor due to chemical materials and the like may be problematic, the space needs to be sealed, in which case an interior of the bearing may be sealed by using a jacket.
Here, when the bearing is exposed to a high temperature or lower temperature environment, a strong stress may be applied to the jacket due to differences between thermal expansion coefficients and temperatures of the bearing housing and the jacket.
An existing general jacket does not have a structure for buffering a stress, and thus the jacket may be subjected to a crack or may be even damaged or leaked.